The present invention relates to a motor. More particularly, the present invention relates to a small DC motor in which a rotor having a shaft fixed with a commutator that is accommodated in a cylindrical motor case having a bottom portion. A permanent magnet is fixed on the inner circumferential face of the bottom portion. Base portions of brushes coming into sliding contact with the commutator are attached to an inner face of a bracket for closing an open portion of the motor case. Lead wires to be connected to the outside are connected to the base portions of the brushes, wherein the lead wire can be easily attached.
Concerning the connecting structure to connect a brush or terminal with a lead wire in a related small DC motor of this type, the following connecting structure is well known. For example, as shown in the related example illustrated in FIG. 4 of JP-A-5-308754 (Pages 1 to 3, FIGS. 1 to 4), after the lead wire and the terminal are positioned and arranged in the bracket, the terminal and the core wire of the lead wire are soldered to each other while heating them.
According to this connecting structure, since the brush or the terminal of the small DC motor and the lead wire are soldered to each other, the following problems may be encountered. At the time of soldering work, flux of soldering is scattered and the brush and the bracket are contaminated by flux. Therefore, quality of soldering is deteriorated. Since it is necessary to add a process of inspection because soldering work is unstable, the manufacturing cost is raised and the quality cannot be stabilized.
In order to solve the above problems, JP-A-5-308754 describes the following lead wire fixing structure. A predetermined cutout portion is provided in at least one of the brush and the terminal, and the lead wire is press-fitted or calked into the cutout portion. Due to this connecting structure, soldering work becomes unnecessary.
However, even in the above lead wire fixing structure of the small DC motor, it is necessary to conduct press-fitting or calking of the lead wire. Therefore, much labor is needed for the fixing work, and quality of the lead wire structure to be fixed by press-fitting or calking can not be stabilized.